Information Sheet
IS13070
Symphyla
Distribution
Symphylans are present in all districts and on most soil types.
Damage often occurs on clay-loam soils in the Herbert valley,
and on coarse-grained granitic loams in the Mossman and
Tully regions.
Damage
Symphylan damage is primarily due to eating out and killing
the apical bud at root-tips. Then, as secondary buds along
the length of the root begin to side shoot, symphylan bore in
and eat them, leaving cylindrical pits (0.5-1.0 mm diameter)
through the white outer layer into the inner core of the root.
The root mass becomes clumped, roots branching again and
again; an effect named ‘coralloid branching’.
Symphylan symptoms are most common in young plant
cane. Damage results in slow growth, and weak tillering and
stooling-out, which can directly or indirectly restrict yield.
Plants develop a short, stunted and side-shot root mass.
With their restricted root-ball, damaged plants wilt easily in
dry weather. Symptoms are usually patchy. Sometimes, rootbuds on setts are eaten out and/or sett-roots are
stunted. In severe cases, all root-buds on the lower nodes of
shoots are destroyed.
Ratoons can also be damaged, typically with few, short stalks
and a restricted root-ball. In most cases, however, other
factors may also be limiting ratooning vigour.
Description
Adult symphylans are elongate, centipede-like arthropods,
white or cream in colour, 5-8 mm long, with long slender
antennae. Young stages have 6-10 pairs of legs; adults 12 pairs.
They can be very difficult to find in the soil.
Biology
Symphylans are present all year. The cycle occupies about
5-6 weeks. Females lay clusters of 10-20 eggs which they tend
until hatched. Symphylans use natural cracks and crevices to
move around and between roots, and are most active in loose
soil or naturally cracking loams.
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(Hanseniella spp.)
Symphylans are primary decomposers, helping to break
down and recycle decaying plant material. Generally their
presence indicates a healthy soil system. Populations can
fluctuate sharply, increasing rapidly if food is available and
then crashing due to drying, lack of food, soil cultivation etc.
A few symphylans (1-2 per shovelful of soil) are almost always
present. Mostly, damage to sugarcane only occurs after the
symphylan population has expanded due to break down of
rotting vegetable matter (eg from a legume crop), and when
that material has gone they congregate on newly planted cane.
Usually, sugarcane growth is only restricted if symphylans are
sufficiently numerous (approximately 10 or more per plant) to
prevent the root-ball from expanding. Damage to plant cane
is usually worsened if growth is slowed due to either cold and
wet conditions, or hot and dry spring conditions.
Management
In some cases, planting furrows (drills) that had been ‘rolled’
after planting showed less damage, probably because
symphylan movement was restricted in the compacted soil
around the setts.
Rapid germination and root growth make spring-plantless
susceptible to damage than earlier plantings. A slightly later
planting date also allows more time for rotting vegetation to
decay and symphylan populations to decline.
Always check that plants are not also being restricted by
factors such as poor nutrient balance before diagnosing
symphylan damage as the cause of poor-growth symptoms.
Even though symphylan-affected plants may not have stooled,
hilling-up generally improves growth as root buds from nodes
higher up the stems are stimulated to germinate. Natural
plant compensation usually evens-out yields over the different
portions of the field. Do not compromise the effectiveness
of fill-in and weed-control operations by delaying these
operations to allow for the ‘slow’ symphylan-affected portions
to stool-out.
Chlorpyrifos (500 g/L) is registered for use against symphylans,
with application onto the billet or sett and adjacent soil at
planting. Aways read the product label and Material Safety
Data Sheet for application rate, conditions of use and safety
equipment.
Information Sheet
IS13070
Field damaged by Symphyla.
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